1. Field of the Invention
The present invention relates generally to an absorbent article for sanitary napkins, pantiliners, incontinence pads, etc. More precisely, the invention relates to such an absorbent article of which the top sheet has a good feel.
2. Description of the Related Art
Absorbent articles are much used these days for sanitary napkins, pantiliners, incontinence pads, disposable diapers and the like for absorbing excretions. Such absorbent articles generally comprise a liquid pervious top sheet to face a wearer (serving as a body facing face), a liquid impervious back sheet, and a liquid absorbing layer sandwiched between the top sheet and the back sheet. The top sheet is directly contacted with the skin of a wearer, so that it is desirable to have a good feel. In addition, since the top sheet directly receives excretions, it is preferable that liquid excretions hardly stay therein so that the top sheet itself does not become stuffy and sticky.
For example, Japanese Unexamined Patent Publication (Kokai) No. Heisei 5-200065 discloses a surface member for absorbent articles, which has a fine embossed pattern on its surface. As having a fine embossed pattern, the surface member disclosed does not have a plastic-like feel, and is not sticky. In this case, this is not sticky in dry, but when wetted, it shall have power of resistance to liquid flow thereon owing to its embossed pattern, and tends to keep the liquid in the recesses on its surface.
International Unexamined Patent Publication (Kohyo) No. Heisei 9-505223 discloses a liquid pervious, porous plastic web containing a particulate material. The web is formed into a top sheet for absorbent articles, and this has a little plastic-like feel. However, the web containing the particulate material is rigid, and the top sheet made of it is poorly flexible.
The present invention has an object to provide an absorbent article of which the top sheet is not sticky even in wet and is highly flexible, thereby all the time having a good feel.
Another object of the invention is to provide an absorbent article of which the top sheet has shape retaining perforations.
According to an aspect of the invention, the absorbent article of the invention may comprise an absorbent layer and a top sheet having a number of perforations and disposed on a body facing surface of the absorbent layer, wherein;
the top sheet is made of a multi-layered resin film having at least two resin layers composing of an outer resin layer exposed outside the body facing surface and at least one inner resin layer disposed nearer to the absorbent layer than the outer resin layer thereto, at least the outer resin layer containing particulate material having a mean particle size of from 2 xcexcm to 20 xcexcm, and the inner resin layer having the resin density smaller than that of the outer resin layer.
With the top sheet of the absorbent article of the invention, the outer resin layer to be kept in direct contact with the skin of a wearer does not have a plastic-like feel, and little liquid remains therein. In its use, therefore, the top sheet does not become stuffy and sticky. On the other hand, the inner resin layer of the top sheet ensures the flexibility of the top sheet. In addition, the shape retaining ability of the perforations formed through the top sheet is good. Therefore, even if the perforations are deformed while the absorbent article is used, they can be readily restored to their original condition.
The top sheet of the absorbent article of the invention may be made of a two-layered resin film composed of an outer resin layer and an inner resin layer; or may be made of a multi-layered resin film having a third resin layer in addition to the outer and inner resin layers. For the latter, for example, the third resin layer may be sandwiched between the outer resin layer and the inner resin layer, or may be disposed inside the inner resin layer. The resin density of the third resin layer may be the same as that of the outer resin layer, or may fall between the resin density of the outer resin layer and that of the inner resin layer.
The inner resin layer is to ensure the flexibility of the top sheet comprising it. Therefore, it is desirable that the inner resin layer does not contain particulate material having a mean particle size of from 2 xcexcm to 20 xcexcm. However, the inner resin layer may contain such particulate material so far as the particulate material content of the inner resin layer is smaller than that of the outer resin layer.
In order to prevent too tight contact of the top sheet to the skin in practical use of the absorbent article, it is desirable that at least a part of the particulate material is exposed outside the outer resin layer.
For example, the resin density of the outer resin layer is at least 0.91 g/cm3, and that of the inner resin layer is at most 0.90 g/cm3.
Preferably, the outer resin layer contains from 30 to 60 parts by weight, relative to 100 parts by weight of the resin that forms the outer resin layer, of the particulate material.
Also preferably, the thickness of the outer resin layer is from 15 to 60% and the thickness of the inner resin layer is from 40 to 85%, relative to 100% of the thickness of the multi-layered resin film. This shall apply to both two-layered resin films and three-layered or more multi-layered resin films for the top sheet.
For example, the thickness of the multi-layered film for the top sheet falls between 20 and 35 xcexcm.
Also for example, the top sheet of the absorbent article of the invention is a three-dimensionally perforated sheet in which the inner wall of each perforation protrudes from the inner surface of the top sheet toward the absorbent layer.
For example, the inner diameter of each perforation in the surface of the top sheet falls between 0.6 and 1.5 mm; the depth of each perforation from its top falls between 0.3 and 0.6 mm; and the distance between the neighboring perforations in the surface of the top sheet falls between 0.05 and 0.2 mm.
At least one resin layer of the multi-layered resin film may optionally contain fine particles having a particle size of from 0.01 xcexcm to 0.5 xcexcm, with the amount of the fine particles being not larger than 5 parts by weight relative to 100 parts by weight of the resin that forms the resin layer.
Containing such fine particles, the transparency of the top sheet may be lowered, and the blood or the like having been absorbed by the absorbent layer could be masked with them. In this case, the fine particles are, for example, titanium oxide particles.
The top sheet made of the multi-layered resin film may be partly bonded to the absorbent layer; or a water-impervious non-woven fabric may be bonded to the inner surface of the top sheet made of the multi-layered resin film to form a combined sheet, and the combined sheet of the top sheet and the non-woven fabric may be partly bonded to the absorbent layer.